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Linux/block/blk-mq-tag.c

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Diff markup

Differences between /block/blk-mq-tag.c (Version linux-4.17.19) and /block/blk-mq-tag.c (Version linux-4.19.206)


** Warning: Cannot open xref database.

  1 /*                                                  1 
  2  * Tag allocation using scalable bitmaps. Uses    
  3  * fairer distribution of tags between multipl    
  4  * is used.                                       
  5  *                                                
  6  * Copyright (C) 2013-2014 Jens Axboe             
  7  */                                               
  8 #include <linux/kernel.h>                         
  9 #include <linux/module.h>                         
 10                                                   
 11 #include <linux/blk-mq.h>                         
 12 #include "blk.h"                                  
 13 #include "blk-mq.h"                               
 14 #include "blk-mq-tag.h"                           
 15                                                   
 16 bool blk_mq_has_free_tags(struct blk_mq_tags *    
 17 {                                                 
 18         if (!tags)                                
 19                 return true;                      
 20                                                   
 21         return sbitmap_any_bit_clear(&tags->bi    
 22 }                                                 
 23                                                   
 24 /*                                                
 25  * If a previously inactive queue goes active,    
 26  */                                               
 27 bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *h    
 28 {                                                 
 29         if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hc    
 30             !test_and_set_bit(BLK_MQ_S_TAG_ACT    
 31                 atomic_inc(&hctx->tags->active    
 32                                                   
 33         return true;                              
 34 }                                                 
 35                                                   
 36 /*                                                
 37  * Wakeup all potentially sleeping on tags        
 38  */                                               
 39 void blk_mq_tag_wakeup_all(struct blk_mq_tags     
 40 {                                                 
 41         sbitmap_queue_wake_all(&tags->bitmap_t    
 42         if (include_reserve)                      
 43                 sbitmap_queue_wake_all(&tags->    
 44 }                                                 
 45                                                   
 46 /*                                                
 47  * If a previously busy queue goes inactive, p    
 48  * be allowed to queue. Wake them up and check    
 49  */                                               
 50 void __blk_mq_tag_idle(struct blk_mq_hw_ctx *h    
 51 {                                                 
 52         struct blk_mq_tags *tags = hctx->tags;    
 53                                                   
 54         if (!test_and_clear_bit(BLK_MQ_S_TAG_A    
 55                 return;                           
 56                                                   
 57         atomic_dec(&tags->active_queues);         
 58                                                   
 59         blk_mq_tag_wakeup_all(tags, false);       
 60 }                                                 
 61                                                   
 62 /*                                                
 63  * For shared tag users, we track the number o    
 64  * and attempt to provide a fair share of the     
 65  */                                               
 66 static inline bool hctx_may_queue(struct blk_m    
 67                                   struct sbitm    
 68 {                                                 
 69         unsigned int depth, users;                
 70                                                   
 71         if (!hctx || !(hctx->flags & BLK_MQ_F_    
 72                 return true;                      
 73         if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hc    
 74                 return true;                      
 75                                                   
 76         /*                                        
 77          * Don't try dividing an ant              
 78          */                                       
 79         if (bt->sb.depth == 1)                    
 80                 return true;                      
 81                                                   
 82         users = atomic_read(&hctx->tags->activ    
 83         if (!users)                               
 84                 return true;                      
 85                                                   
 86         /*                                        
 87          * Allow at least some tags               
 88          */                                       
 89         depth = max((bt->sb.depth + users - 1)    
 90         return atomic_read(&hctx->nr_active) <    
 91 }                                                 
 92                                                   
 93 static int __blk_mq_get_tag(struct blk_mq_allo    
 94                             struct sbitmap_que    
 95 {                                                 
 96         if (!(data->flags & BLK_MQ_REQ_INTERNA    
 97             !hctx_may_queue(data->hctx, bt))      
 98                 return -1;                        
 99         if (data->shallow_depth)                  
100                 return __sbitmap_queue_get_sha    
101         else                                      
102                 return __sbitmap_queue_get(bt)    
103 }                                                 
104                                                   
105 unsigned int blk_mq_get_tag(struct blk_mq_allo    
106 {                                                 
107         struct blk_mq_tags *tags = blk_mq_tags    
108         struct sbitmap_queue *bt;                 
109         struct sbq_wait_state *ws;                
110         DEFINE_WAIT(wait);                        
111         unsigned int tag_offset;                  
112         bool drop_ctx;                            
113         int tag;                                  
114                                                   
115         if (data->flags & BLK_MQ_REQ_RESERVED)    
116                 if (unlikely(!tags->nr_reserve    
117                         WARN_ON_ONCE(1);          
118                         return BLK_MQ_TAG_FAIL    
119                 }                                 
120                 bt = &tags->breserved_tags;       
121                 tag_offset = 0;                   
122         } else {                                  
123                 bt = &tags->bitmap_tags;          
124                 tag_offset = tags->nr_reserved    
125         }                                         
126                                                   
127         tag = __blk_mq_get_tag(data, bt);         
128         if (tag != -1)                            
129                 goto found_tag;                   
130                                                   
131         if (data->flags & BLK_MQ_REQ_NOWAIT)      
132                 return BLK_MQ_TAG_FAIL;           
133                                                   
134         ws = bt_wait_ptr(bt, data->hctx);         
135         drop_ctx = data->ctx == NULL;             
136         do {                                      
137                 /*                                
138                  * We're out of tags on this h    
139                  * pending IO submits before g    
140                  * some to complete.              
141                  */                               
142                 blk_mq_run_hw_queue(data->hctx    
143                                                   
144                 /*                                
145                  * Retry tag allocation after     
146                  * as running the queue may al    
147                  */                               
148                 tag = __blk_mq_get_tag(data, b    
149                 if (tag != -1)                    
150                         break;                    
151                                                   
152                 prepare_to_wait_exclusive(&ws-    
153                                                   
154                                                   
155                 tag = __blk_mq_get_tag(data, b    
156                 if (tag != -1)                    
157                         break;                    
158                                                   
159                 if (data->ctx)                    
160                         blk_mq_put_ctx(data->c    
161                                                   
162                 io_schedule();                    
163                                                   
164                 data->ctx = blk_mq_get_ctx(dat    
165                 data->hctx = blk_mq_map_queue(    
166                 tags = blk_mq_tags_from_data(d    
167                 if (data->flags & BLK_MQ_REQ_R    
168                         bt = &tags->breserved_    
169                 else                              
170                         bt = &tags->bitmap_tag    
171                                                   
172                 finish_wait(&ws->wait, &wait);    
173                 ws = bt_wait_ptr(bt, data->hct    
174         } while (1);                              
175                                                   
176         if (drop_ctx && data->ctx)                
177                 blk_mq_put_ctx(data->ctx);        
178                                                   
179         finish_wait(&ws->wait, &wait);            
180                                                   
181 found_tag:                                        
182         return tag + tag_offset;                  
183 }                                                 
184                                                   
185 void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx    
186                     struct blk_mq_ctx *ctx, un    
187 {                                                 
188         if (!blk_mq_tag_is_reserved(tags, tag)    
189                 const int real_tag = tag - tag    
190                                                   
191                 BUG_ON(real_tag >= tags->nr_ta    
192                 sbitmap_queue_clear(&tags->bit    
193         } else {                                  
194                 BUG_ON(tag >= tags->nr_reserve    
195                 sbitmap_queue_clear(&tags->bre    
196         }                                         
197 }                                                 
198                                                   
199 struct bt_iter_data {                             
200         struct blk_mq_hw_ctx *hctx;               
201         busy_iter_fn *fn;                         
202         void *data;                               
203         bool reserved;                            
204 };                                                
205                                                   
206 static bool bt_iter(struct sbitmap *bitmap, un    
207 {                                                 
208         struct bt_iter_data *iter_data = data;    
209         struct blk_mq_hw_ctx *hctx = iter_data    
210         struct blk_mq_tags *tags = hctx->tags;    
211         bool reserved = iter_data->reserved;      
212         struct request *rq;                       
213                                                   
214         if (!reserved)                            
215                 bitnr += tags->nr_reserved_tag    
216         rq = tags->rqs[bitnr];                    
217                                                   
218         /*                                        
219          * We can hit rq == NULL here, because    
220          * test and set the bit before assinin    
221          */                                       
222         if (rq && rq->q == hctx->queue)           
223                 iter_data->fn(hctx, rq, iter_d    
224         return true;                              
225 }                                                 
226                                                   
227 static void bt_for_each(struct blk_mq_hw_ctx *    
228                         busy_iter_fn *fn, void    
229 {                                                 
230         struct bt_iter_data iter_data = {         
231                 .hctx = hctx,                     
232                 .fn = fn,                         
233                 .data = data,                     
234                 .reserved = reserved,             
235         };                                        
236                                                   
237         sbitmap_for_each_set(&bt->sb, bt_iter,    
238 }                                                 
239                                                   
240 struct bt_tags_iter_data {                        
241         struct blk_mq_tags *tags;                 
242         busy_tag_iter_fn *fn;                     
243         void *data;                               
244         bool reserved;                            
245 };                                                
246                                                   
247 static bool bt_tags_iter(struct sbitmap *bitma    
248 {                                                 
249         struct bt_tags_iter_data *iter_data =     
250         struct blk_mq_tags *tags = iter_data->    
251         bool reserved = iter_data->reserved;      
252         struct request *rq;                       
253                                                   
254         if (!reserved)                            
255                 bitnr += tags->nr_reserved_tag    
256                                                   
257         /*                                        
258          * We can hit rq == NULL here, because    
259          * test and set the bit before assinin    
260          */                                       
261         rq = tags->rqs[bitnr];                    
262         if (rq)                                   
263                 iter_data->fn(rq, iter_data->d    
264                                                   
265         return true;                              
266 }                                                 
267                                                   
268 static void bt_tags_for_each(struct blk_mq_tag    
269                              busy_tag_iter_fn     
270 {                                                 
271         struct bt_tags_iter_data iter_data = {    
272                 .tags = tags,                     
273                 .fn = fn,                         
274                 .data = data,                     
275                 .reserved = reserved,             
276         };                                        
277                                                   
278         if (tags->rqs)                            
279                 sbitmap_for_each_set(&bt->sb,     
280 }                                                 
281                                                   
282 static void blk_mq_all_tag_busy_iter(struct bl    
283                 busy_tag_iter_fn *fn, void *pr    
284 {                                                 
285         if (tags->nr_reserved_tags)               
286                 bt_tags_for_each(tags, &tags->    
287         bt_tags_for_each(tags, &tags->bitmap_t    
288 }                                                 
289                                                   
290 void blk_mq_tagset_busy_iter(struct blk_mq_tag    
291                 busy_tag_iter_fn *fn, void *pr    
292 {                                                 
293         int i;                                    
294                                                   
295         for (i = 0; i < tagset->nr_hw_queues;     
296                 if (tagset->tags && tagset->ta    
297                         blk_mq_all_tag_busy_it    
298         }                                         
299 }                                                 
300 EXPORT_SYMBOL(blk_mq_tagset_busy_iter);           
301                                                   
302 int blk_mq_tagset_iter(struct blk_mq_tag_set *    
303                          int (fn)(void *, stru    
304 {                                                 
305         int i, j, ret = 0;                        
306                                                   
307         if (WARN_ON_ONCE(!fn))                    
308                 goto out;                         
309                                                   
310         for (i = 0; i < set->nr_hw_queues; i++    
311                 struct blk_mq_tags *tags = set    
312                                                   
313                 if (!tags)                        
314                         continue;                 
315                                                   
316                 for (j = 0; j < tags->nr_tags;    
317                         if (!tags->static_rqs[    
318                                 continue;         
319                                                   
320                         ret = fn(data, tags->s    
321                         if (ret)                  
322                                 goto out;         
323                 }                                 
324         }                                         
325                                                   
326 out:                                              
327         return ret;                               
328 }                                                 
329 EXPORT_SYMBOL_GPL(blk_mq_tagset_iter);            
330                                                   
331 void blk_mq_queue_tag_busy_iter(struct request    
332                 void *priv)                       
333 {                                                 
334         struct blk_mq_hw_ctx *hctx;               
335         int i;                                    
336                                                   
337                                                   
338         queue_for_each_hw_ctx(q, hctx, i) {       
339                 struct blk_mq_tags *tags = hct    
340                                                   
341                 /*                                
342                  * If not software queues are     
343                  * hardware queue, there's not    
344                  */                               
345                 if (!blk_mq_hw_queue_mapped(hc    
346                         continue;                 
347                                                   
348                 if (tags->nr_reserved_tags)       
349                         bt_for_each(hctx, &tag    
350                 bt_for_each(hctx, &tags->bitma    
351         }                                         
352                                                   
353 }                                                 
354                                                   
355 static int bt_alloc(struct sbitmap_queue *bt,     
356                     bool round_robin, int node    
357 {                                                 
358         return sbitmap_queue_init_node(bt, dep    
359                                        node);     
360 }                                                 
361                                                   
362 static struct blk_mq_tags *blk_mq_init_bitmap_    
363                                                   
364 {                                                 
365         unsigned int depth = tags->nr_tags - t    
366         bool round_robin = alloc_policy == BLK    
367                                                   
368         if (bt_alloc(&tags->bitmap_tags, depth    
369                 goto free_tags;                   
370         if (bt_alloc(&tags->breserved_tags, ta    
371                      node))                       
372                 goto free_bitmap_tags;            
373                                                   
374         return tags;                              
375 free_bitmap_tags:                                 
376         sbitmap_queue_free(&tags->bitmap_tags)    
377 free_tags:                                        
378         kfree(tags);                              
379         return NULL;                              
380 }                                                 
381                                                   
382 struct blk_mq_tags *blk_mq_init_tags(unsigned     
383                                      unsigned     
384                                      int node,    
385 {                                                 
386         struct blk_mq_tags *tags;                 
387                                                   
388         if (total_tags > BLK_MQ_TAG_MAX) {        
389                 pr_err("blk-mq: tag depth too     
390                 return NULL;                      
391         }                                         
392                                                   
393         tags = kzalloc_node(sizeof(*tags), GFP    
394         if (!tags)                                
395                 return NULL;                      
396                                                   
397         tags->nr_tags = total_tags;               
398         tags->nr_reserved_tags = reserved_tags    
399                                                   
400         return blk_mq_init_bitmap_tags(tags, n    
401 }                                                 
402                                                   
403 void blk_mq_free_tags(struct blk_mq_tags *tags    
404 {                                                 
405         sbitmap_queue_free(&tags->bitmap_tags)    
406         sbitmap_queue_free(&tags->breserved_ta    
407         kfree(tags);                              
408 }                                                 
409                                                   
410 int blk_mq_tag_update_depth(struct blk_mq_hw_c    
411                             struct blk_mq_tags    
412                             bool can_grow)        
413 {                                                 
414         struct blk_mq_tags *tags = *tagsptr;      
415                                                   
416         if (tdepth <= tags->nr_reserved_tags)     
417                 return -EINVAL;                   
418                                                   
419         tdepth -= tags->nr_reserved_tags;         
420                                                   
421         /*                                        
422          * If we are allowed to grow beyond th    
423          * a new set of tags before freeing th    
424          */                                       
425         if (tdepth > tags->nr_tags) {             
426                 struct blk_mq_tag_set *set = h    
427                 struct blk_mq_tags *new;          
428                 bool ret;                         
429                                                   
430                 if (!can_grow)                    
431                         return -EINVAL;           
432                                                   
433                 /*                                
434                  * We need some sort of upper     
435                  * no valid use cases should r    
436                  */                               
437                 if (tdepth > 16 * BLKDEV_MAX_R    
438                         return -EINVAL;           
439                                                   
440                 new = blk_mq_alloc_rq_map(set,    
441                 if (!new)                         
442                         return -ENOMEM;           
443                 ret = blk_mq_alloc_rqs(set, ne    
444                 if (ret) {                        
445                         blk_mq_free_rq_map(new    
446                         return -ENOMEM;           
447                 }                                 
448                                                   
449                 blk_mq_free_rqs(set, *tagsptr,    
450                 blk_mq_free_rq_map(*tagsptr);     
451                 *tagsptr = new;                   
452         } else {                                  
453                 /*                                
454                  * Don't need (or can't) updat    
455                  * remain static and should ne    
456                  */                               
457                 sbitmap_queue_resize(&tags->bi    
458         }                                         
459                                                   
460         return 0;                                 
461 }                                                 
462                                                   
463 /**                                               
464  * blk_mq_unique_tag() - return a tag that is     
465  * @rq: request for which to compute a unique     
466  *                                                
467  * The tag field in struct request is unique p    
468  * all hardware queues. Hence this function th    
469  * hardware context index in the upper bits an    
470  * the lower bits.                                
471  *                                                
472  * Note: When called for a request that is que    
473  * queue, the hardware context index is set to    
474  */                                               
475 u32 blk_mq_unique_tag(struct request *rq)         
476 {                                                 
477         struct request_queue *q = rq->q;          
478         struct blk_mq_hw_ctx *hctx;               
479         int hwq = 0;                              
480                                                   
481         if (q->mq_ops) {                          
482                 hctx = blk_mq_map_queue(q, rq-    
483                 hwq = hctx->queue_num;            
484         }                                         
485                                                   
486         return (hwq << BLK_MQ_UNIQUE_TAG_BITS)    
487                 (rq->tag & BLK_MQ_UNIQUE_TAG_M    
488 }                                                 
489 EXPORT_SYMBOL(blk_mq_unique_tag);                 
490                                                   

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